Pneumatic pumping system



Jan. 15, 1957 R. c. CLARK, JR 2,777,399

PNEUMATIC PUMPING SYSTEM Filed July 15, 1953 Q 2 Sheets-Sheet 1 MAKEUP INVENTOR. F0C0f cam/(.112. W BY 1 iTTOR/VEXS- Jan. 15, 1957 R. c. CLARK, JR

PNEUMATIC PUMPING SYSTEM 2 Sheets-Sheet 2 Filed July 15,.1953

FIG. 2

ATTORNEYS United States Patent PNEUMATIC PUMPING SYSTEM Roscoe C. Clark, Jr., Midland, Tex., assignor to Continental Oil Company, Ponca City, Olden, a corporation of Delaware Application July 15, 1953, Serial No. 368,159

2 Claims. (Cl. 103-234) This invention relates to a device for forcing oil out of an oil well wherein fluid pressure is utilized as the opera-ting agency.

Heretofore sucker rod pumps have been the most effective means for lifting oil to the surface from the bottom of oil wells. The use of sucker rods have in general been limited to wells less than 8,000 to 10,000 feet in depth due primarily to the limitations of the sucker rods. Ga lift pumps have also been used to a rather limited extent, however, no provision has been made heretofore when using such pumps for imposing a positive pressure upon the liquid contained in the annular space between the well casing and the production tubing.

it is, therefore, one object of the present invention to provide a pump which will be useful for pumping oil at well depths up to and exceeding 10,000 feet.

It is another object of the present invention to provide :a pump which is simple to operate and is comparatively simple and inexpensive to manufacture.

Yet another object of the invention is to provide means by which the oil or liquid accumulation chamber of the pump after discharge can be quickly recharged with oil or liquid.

In brief, my invention employs compressed gas or any other suitable impelling or pressure fluid as a motivating medium by which the liquid in the well i pumped to the surface. In general, a suitable pressure fluid is one which is lighter than the crude oil being produced, as for example, a non-oxidizing gas such as nitrogen, carbon dioxide, or natural gas. The liquid accumulation chamher is immersed or partially immersed in the liquid in or near the bottom of the well and is provided with suitable valve means which will permit the liquid to flow in but not out and out but not in at the base and top of the accumulation chamber, respectively. The pressure fluid is delivered to the bottom portion of the well adjacent to the work to be performed where it is intermittently applied with substantially no loss either in volume or pressure. A continuous series of short slugs of liquid from the well is projected up the annular space between the two tubing strings to the surface above the well. Provision is made also for reducing the pressure in the accumulation chamber after its liquid contents have been discharged and applying a pressure above the liquid column outside the liquid accumulation chamber, thus ensuring that the latter will be rapidly refilled.

The invention is hereinafter described with reference to the accompanying drawings, in which Figure 1 is a diagrammatic vertical section of apparatus provided for raising a liquid, such as oil, or water from a well. In carrying the invention into effect according to one construction diagrammatically illustrated, casing 1 of the oil well may as usual comprise a number of connected link sections of the casing and the annular tubing 2 a number of connected tube lengths, the lower end of the latter comprising the liquid accumulation chamber 4. A bell or inner chamber 9 open at the bottom is fitted within the accumulation chamber so as to provide a vertical passageway between the two so that when the accumulation chamber is subjected to a fluid pressure the oil or other liquid contained therein is forced downwardly and then upwardly through the vertical passageway and eventually to the surface. At the bottom of the liquid accumulation chamber is an inwardly opening check valve 5 which permits the oil or the liquid at the bottom of the well or here hole to enter and to accumulate in the liquid accumulation chamber but prevents the return of the oil into the casing or bore hole, or the operating gas under pressure from entering the bore hole or well formation. At the top of the liquid accumulation chamber is an outwardly opening check valve 7 which will permit oil or other liquid contained therein to pass upwardly when being so forced by the pressure fluid but prevents its return into the liquid accumulation chamber. Compressor 13 may be used to remove gas from casing 10 when the well also produces gas. Gas in excess of that needed to .restore the pressure of chamber 15 may be withdrawn through valve 23. If the well is a non-ga producer, make-up gas may be added to the system through valve 22. Preferably, the pump should be so operated as to prevent the entrance of the pressure fluid into the production tubing. This can be accomplished by several methods including preferably the cyclic application and reduction of p 'essure through the macaroni tubing 3 to the bell of the accumulation chamber or by the insertion of a floating piston with suitable stops in the bottom of the bell. The latter is illustrated by Figure 2 wherein 26 represents the floating piston and 27 denotes the piston stops.

Operation of the pump can be described referring to Figure l asfollo-ws: Assuming a quantity of oil has been forced through line 8 by gas pressure in string 3 through open valve 17 from pressure chamber 15; valve 17 is then closed, blow down valve 18 is opened, valve 12 closed, and gas pressure in string 3 is blown down through lines 16, 19, and valve 18 into the annular casing space 10, wherein the rising pressure will urge oil contained therein to flow into the liquid accumulation chamber 4 through check valve 5. Upon substantial blow down into casing 10, valve 12 is opened and the pump compressor 13 removes gas from casing 10 through lines 14 and 11, compressing it into chamber 15 through line 20 and valve 21, valves 22 and 23 being closed, to restore the required pressure therein for the next pumping stroke. If desired, the gas pressure in string 3 and casing 10 may be reduced to atmospheric or lower pressure. The next pumping cycle is resumed, when the pump bell or liquid accumulation chamber has been filled with oil, by closing blow down valve 18 and opening the pressure supply valve 17, whereupon gas under pressure flows from cham ber 15 through lines 24 and 16 to macaroni string 3 to force oil from the pump bell into the production tube 2 from which oil flows out through line 8.

A pneumatic pump as illustrated in Figure l was installed in a well 15,000 feet in depth provided with a casing seven inches in diameter and which had a liquid head of 1,000 feet above the producing formation. The pump within the casing consisted of a string of ZMt-inch diameter production tubing 14,300 feet long to which was attached the liquid accumulation chamber 4 inches in diameter and 700 feet in length. Inside the production tubing and running the length thereof was fitted a macaroni string of A-inch pipe. This pump was operated at the rate of 11 cycles per day (24 hours) at a stroke pressure of 5,000 p. s. i. g. producing oil at the rate of barrels per day. The blow down pressure into the casing was about 200 p. s. i. g., which aided in filling the liquid accumulation chamber. This particular well produced gas in excess over that required for the pumping operations.

The length of the liquid accumulation chamber and its location in the well can be varied from well to well to suit the height and quantity of the liquid in the production zone in the well.

A fewrof the advantages attained by my invention are the following:

I. The operation of the pump is controlled completely from the surface.

2. The pump will effectively and efficiently lift all of the liquid out of the well up to the capacity of the pump as fast as it accumulates, irrespective of the the back pressure held on the casing or bottom hole pressure in the well.

3. All of the formation gas produced from the well is recovered without interfering with the functioning of the pump.

4. The use of the pump is not limited as to depth.

5. The apparatus is simple and inexpensive to manufacture, has few moving parts, and requires a minimum of machine work in producing it.

Gas when used as a motivating fluid in the well may be supplied at the desired pressure, or compressed on the surface to whatever pressure is necessary to meet the depth and productivity conditions and is forced or otherwise supplied into the string of pressure line tubing 3. The lower perforated end of string of casing 1 is set in the fluid bearing strata in the usual manner and is immersed in, and receives, liquid such as oil thereinto, the level assumed by the oil varying according to the productiveness or bottom hole pressure of the well and the back pressure exerted against the oil bearing formation by facilities at the surface.

From the foregoing description of the means for accomplishing the results sought, it is apparent that I have devised a practical and efficient construction for carrying out the desired objects of the invention as regards a simple and economical unit of the character described, and while the foregoing represents a preferred embodiment of the invention, various modifications are possible. As for example, a conventional sucker rod pumping arrangement may be combined with a pneumatic pump. This modification provides for raising oil from extreme depths to a level where a sucker rod pump will operate. It is, therefore, contemplated to cover all changes or modifications as may fall within the scope of the appended claims.

I claim:

l. In a fluid operated pumping apparatus for raising charges of liquid in a well which comprises in combination: a source of fluid under pressure, a well head, a casing, 21 tubing within said casing extending downwardly from the well head into the liquid to be pumped wherein the outside diameter of said tubing is less than the inside diameter of said casing, a closure in the lower end of said tubing, a second closure in said tubing above said first mentioned closure thus forming a liquid accumulation chamber, a chcck valve in said first mentioned closure to prevent the flow of liquids out of said liquid accumulation chamber, a check valve in said second mentioned closure to prevent the flow of well liquids into said liquid accumulation chamber, a bell open at the bottom Within said accumulation chamber rigidly mounted thereon and extending downwardly from the upper portion of said accumulation chamber, and terminating at a point above the first mentioned closure, wherein the outside diameter of said bell is less than the inside diam cter of said accumulation chamber thus providing a vertical passageway between said bell and said accumulation chamber, a gas injection tube connected to the upper end of said bell, and valved conduits connecting said source to said casing and said gas injection tube, whereby fiuid under pressure may be supplied to said casing, and, alternately, to said gas injection tube.

2. The pumping apparatus of claim 1 wherein the bell is fitted with a floating piston adapted to travel freely within said bell from a point near the top to a point near the bottom of said bell.

Rettig Sept. 10, 1907 Hawley Oct. 9, 1951 

